A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 4.5 m/s. The car is a distance d away. The bear is 24 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d? In meters. I know the bear is at D+24.. I don't really know how to start this though.